US cities that have the worst traffic

American commuters collectively spent 8 billion hours stuck in traffic last year, a new analysis shows.

The improving economy is partly to blame for the worsening traffic conditions, according to INRIX, a Washington-state-based company that provides transportation analytics for entities like government agencies.

The company's 2015 Traffic Scorecard, released today, explains: "Urbanization continues to drive increased congestion in many major cities worldwide. Strong economies, population growth, higher employment rates and declining gas prices have resulted in more drivers on the road — and more time wasted in traffic."

For the latest scorecard, INRIX examined traffic conditions in the United States and roughly a dozen European countries.

Congestion was worst in the U.S., with the average commuter spending nearly 50 hours in traffic over the course of the year. In Europe, Belgium saw the worst congestion, with the average commuter spending 44 hours in traffic.

At a city level, half of the 10 worst metropolitan areas for congestion — including four of the worst five — are located in the U.S.:

Trulia examined commute length rather than congestion delay length, but the cities it identified as having the longest commutes include many of the same cities INRIX identified has having the worst congestion delays:

New York City (average commute is 34.7 minutes)

Long Island, New York (33 minutes)

Washington, D.C. (32.8 minutes)

Newark, New Jersey (31.1 minutes)

Chicago, (30.8 minutes)

Boston (30.4 minutes)

Oakland, California (29.9 minutes)

Riverside-San Bernardino, California (29.8 minutes)

Baltimore, Maryland (29.4 minutes)

Atlanta (29.2 minutes)

How does your commute compare with the country's worst? Share your thoughts below or on Facebook.